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rewrite Lock-It-Up patcher to preserve contents of 0x200 [fixes Number Crunchers, The Desecration, others]

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4am 2021-04-08 10:51:29 -04:00
parent ddc2f67b63
commit fecbcd1e1b
1 changed files with 39 additions and 8 deletions
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47
src/patchers/jmpbbfe.a
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@ -1,5 +1,6 @@
;-------------------------------
; #JMPBBFE
; marketed as 'Lock-It-Up'
; boot0 jumps to ($BBFE) instead of ($08FD)
; for a weakbits check at $BB00
;
@ -96,15 +97,45 @@ _jmpbbfe
bpl .exit
lda gIsBoot0 ; if DOS 3.3 boot0 loader
bne .exit
ldx #$4A
ldy #$03
jsr compare ; and T00,S00,$4A ==
!byte $6C,$FE,$BB
bcs .exit ; passport-test-suite/Quadrilaterals.woz [C=0] matches
lda #$00
ldx #$4B
ldy #$02
jsr modify ; then set T00,S00,$4B =
!byte $FD,08
jsr compare ; and T00,S00,$4B ==
!byte $FE,$BB
bcs .exit
; variation 1 (common)
lda #$05
ldx #$20
tay
jsr compare
!byte $A9,WILDCARD
!byte $8D,$00,$02
bcc .yes ; passport-test-suite/Quadrilaterals.woz [C=0] matches
; variation 2 (earlier, less common)
ldx #$19
tay
jsr compare
!byte $A9,WILDCARD
!byte $8D,$00,$02
bcs .exit
.yes stx + ; byte offset (varies)
inx
inx
inx
inx
inx
ldy #$03
jsr modify
!byte $6C,$FD,$08
ldx #$FE
ldy #$01
jsr modify
+ !byte $FD ; SMC (byte offset of new entry point)
.exit
}